-+TCK

=Technological Content Knowledge (TCK)=

Although technology constrains the kinds of representations possible, newer technologies often afford newer and more varied representations and greater flexibility in navigating across these representations. Teachers need to know not just the subject matter they teach, but also **the manner in which the subject matter can be changed by the application of technology.**

For example, consider Geometer’s Sketchpad as a tool for teaching geometry. This allows students to play with shapes and form, making it easier to construct standard geometry proofs. In this regard, the software program merely emulates what was done earlier when learning geometry. However, the computer program does more than that. By allowing students to “play” with geometrical constructions, it also **changes the nature of learning geometry** itself – proofs by construction are a form of representation in mathematics that was not available prior to this technology. Similar arguments can be made for a range of other software products.

Understanding the impact of technology on the practices and knowledge of a given discipline is critical if we are to develop appropriate technological tools for educational purposes. The ch oice of technologies affords and constrains the types of possible representation ** s ** that can be used. Technology constraints the types of possible representations but conversely affords the construction of newer and more varied representations. Furthermore, technological tools can provide a greater degree of flexibility in navigating across these representations.

Thus, we can define **TCK as an understanding of the manner in which technology and content influence and constrain one another**. Teachers need to master more than the subject matter they teach, they must also have a deep understanding of the manner in which the subject matter (or the kinds of representations that can be constructed) can be changed by the application of technology. Teachers need to understand which specific technologies are best suited for addressing subject-matter learning in their domains and how the content dictates or perhaps even changes the technology - or vice versa.